rmail-confirm-expunge

rmail-confirm-expunge is a variable defined in `rmail.el'.
Its value is

y-or-n-p

• This variable may be risky if used as a file-local variable.

Documentation:
Whether and how to ask for confirmation before expunging deleted messages.
The value, if non-nil is a function to call with a question (string)
as argument, to ask the user that question.

You can customize this variable.

This variable was introduced, or its default value was changed, in version 21.1 of Emacs.